This section provides background information related to the present disclosure which is not necessarily prior art.
Present common cryptographic algorithms mainly include symmetric cryptographic algorithms and public-key cryptographic algorithms. The symmetric cryptographic algorithm performs an encryption operation and a decryption operation using a same key. Communicating parties keep their shared keys secret. The symmetric cryptographic algorithm is mainly used for performing rapid data encryption and decryption. In the public-key cryptographic algorithms, keys are generated in pairs. Each pair of keys consists of a public key and a private key. In the practical application of the public-key cryptographic algorithm, the public key is publicly known, while the private key is known only by the owner. In a public-key cryptographic algorithm method for signature systems, a message is encrypted with the private key (called “signing a message”) and a digital signature is then obtained. The digital signature is decrypted with the public key to authenticate the digital signature (called “verifying a signature”). In a public-key cryptographic algorithm used for an encryption system, data is encrypted with the public key. The encrypted data is decrypted with the private key to obtain the plain-text data.